A main valve core control circuit

Abstract

The present application discloses a main valve core control circuit, which is applied to the main valve core control of a cartridge valve. The main valve core is sealed and slidably installed on the valve body of the cartridge valve, and is formed with an upper control chamber and a lower control chamber for controlling the movement of the main valve core. The main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber and the lower control chamber. The opening of the main valve core is adjusted by controlling the opening of each pilot control valve. Beneficial effects of the present application: By independently controlling the upper control chamber and the lower control chamber of the cartridge valve with hydraulic pilot control, the position of the main valve core can be accurately and quickly controlled, and different back pressures can be adjusted according to different needs. Compared with the traditional method, while increasing the control stability of the main valve core, the response speed can also be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of valve control technology, and in particular to a main valve core control circuit. Background Art

[0002] like Figure 1 As shown, the pilot valve of the current plug-in two-way servo valve uses a three-position four-way servo valve 02, and in order to increase the flow gain of the pilot valve at zero position, the valve core is generally made into a positive opening form at zero position. However, the positive opening pilot valve will have leakage at zero position, causing the position of the main valve core to fluctuate due to the leakage of the pilot valve, and the main valve core needs to be monitored and adjusted in real time.

[0003] Since the movement of the pilot valve oil port is interlocked, Figure 1 As shown, it is assumed that the P port of the pilot valve is connected to A and the B port is connected to T, that is, when the opening of the P port to A becomes larger, the opening of the B port to T will also become larger, which will cause the return oil pressure of the B port to T to decrease when the oil returns, that is, the back pressure decreases; the back pressure decreases will cause the stability of the system to deteriorate. At the same time, for the control of the main valve core, in order to avoid overshoot of the main valve core movement, the main valve core generally needs to slow down when it is about to move to the target position. During the deceleration, the opening of the pilot valve will decrease, and the back pressure will increase at this time. However, during the process of increasing back pressure, the opening of the pilot valve inlet is also decreasing until it returns to zero position; because the valve core is in a positive opening form when returning to zero position, the pilot valve needs to be continuously fine-tuned left and right near zero position to ensure the accuracy of the main valve core position, which will greatly increase the control difficulty of the main valve core and reduce the response speed of the servo valve. Summary of the invention

[0004] One of the purposes of the present application is to provide a main valve core control circuit that can solve at least one defect in the above-mentioned background technology.

[0005] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: a main valve core control circuit, applied to the main valve core control of the cartridge valve, the main valve core is sealingly and slidably installed on the valve body of the cartridge valve, and forms an upper control chamber and a lower control chamber for controlling the movement of the main valve core; the main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber and the lower control chamber; the opening of the main valve core is adjusted by controlling the opening of each of the pilot control valves; the pressure difference between the upper control chamber and the lower control chamber of the main valve core during the opening adjustment process is cooperatively controlled through a hydraulic bridge structure formed by the cooperation of each of the pilot control valves.

[0006] Preferably, the number of the pilot control valves is a pair, and the two pilot control valves form an A-bridge structure by being connected to each other and to the upper control chamber and the lower control chamber, and the opening of the main valve core is adjusted by the A-bridge structure.

[0007] Preferably, the cartridge valve also includes a spring for resetting the main valve core, and the outlet of the upper control chamber is connected to the oil tank; the inlet of one of the pilot control valves is connected to the oil pump, and the outlet is connected to the inlet of the lower control chamber and the inlet of the other pilot control valve, and the outlet of the other pilot control valve is connected to the outlet of the upper control chamber, so that the A-bridge structure is formed between the two pilot control valves.

[0008] Preferably, the number of the pilot control valves is a pair, and the two pilot control valves are respectively connected to the upper control chamber and the lower control chamber to form a double C-bridge structure, and then the opening of the main valve core is adjusted by the double C-bridge structure.

[0009] Preferably, the outlets of the upper control chamber and the lower control chamber are both connected to the oil tank, the inlets of the two pilot control valves are both connected to the oil pump, and the outlets of the two pilot control valves are respectively connected to the inlets of the upper control chamber and the lower control chamber, so that each pilot control valve forms a C-bridge structure.

[0010] Preferably, fixed damping for increasing the return oil pressure is installed in the pipelines connecting the outlets of the upper control chamber and the lower control chamber with the oil tank.

[0011] Preferably, the number of the pilot control valves is two pairs, and the upper control chamber and the lower control chamber are each connected to a pair of the pilot control valves, so that the two pairs of the pilot control valves form a double A-bridge structure to adjust the opening of the main valve core.

[0012] Preferably, the inlets of a pair of the pilot control valves are connected to the oil pump, and the outlets are respectively connected to the inlets of the upper control chamber and the lower control chamber; the outlets of the upper control chamber and the lower control chamber are connected to the oil tank through the pilot control valves, so that an A-bridge structure is formed between the pair of pilot control valves corresponding to the upper control chamber and the lower control chamber respectively.

[0013] Preferably, the main valve core control circuit also includes a displacement sensor and a control circuit. The displacement sensor is installed on the valve body of the cartridge valve to monitor the movement distance of the main valve core. The control circuit is suitable for receiving the displacement data sent by the displacement sensor and sending corresponding opening control signals to each pilot control valve according to a preset opening.

[0014] Preferably, the control circuit includes a controller and a comparator; the comparator is suitable for receiving the displacement data sent by the displacement sensor and comparing it with the preset opening, and the controller is suitable for generating a corresponding opening control signal according to the comparison result of the comparator to send it to each of the pilot control valves respectively.

[0015] Compared with the prior art, the beneficial effects of this application are:

[0016] By independently controlling the upper and lower control chambers of the cartridge valve with hydraulic pilot control, the position of the main valve core can be accurately and quickly controlled, and different back pressures can be adjusted according to different needs. Compared with traditional methods, this can effectively improve the response speed while increasing the control stability of the main valve core. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of a circuit structure for pilot controlling a cartridge valve through a three-position four-way servo valve in the prior art.

[0018] Figure 2 This is a schematic diagram of the circuit structure for pilot control of a cartridge valve according to one of the embodiments of the present application.

[0019] Figure 3 This is a schematic diagram of the circuit structure for pilot controlling a cartridge valve according to another embodiment of the present application.

[0020] Figure 4 This is a schematic diagram of the circuit structure for pilot controlling a cartridge valve according to yet another embodiment of the present application.

[0021] In the figure: cartridge valve 01, main valve core 011, spring 012, upper control chamber 013, lower control chamber 014, servo valve 02, displacement sensor 10, first pilot control valve 11, second pilot control valve 12, controller 13, comparator 14, third pilot control valve 15, fourth pilot control valve 16. DETAILED DESCRIPTION

[0022] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0023] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0025] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0027] The terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0028] In order to facilitate the understanding of this solution, the structure of the cartridge valve 01 can be briefly introduced first. Figure 1 As shown, the cartridge valve 01 includes a valve body and a main valve core 011, and the main valve core 011 is sealed and slidably installed in the valve body; the opening of the cartridge valve 01 is adjusted by the different moving distances of the main valve core 011. The main valve core 011 can form an upper control chamber 013 and a lower control chamber 014 with the inner cavity of the valve body through a partially protruding shaft section in the valve body; wherein the upper control chamber 013 is used to drive the main valve core 011 to move to reduce the opening, and the lower control chamber 014 is used to drive the main valve core 011 to move to increase the opening.

[0029] One of the preferred embodiments of the present application is as follows: Figures 2 to 4 As shown, a main valve core control circuit is used to control the main valve core 011 of the above-mentioned cartridge valve 01. The main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber 013 and the lower control chamber 014; the opening of the main valve core 011 is adjusted by controlling the opening of each pilot control valve. The pressure difference between the upper control chamber 013 and the lower control chamber 014 of the main valve core 011 during the opening adjustment process is coordinated and controlled by the hydraulic bridge structure formed by the cooperation of each pilot control valve.

[0030] It is understandable that in Figure 1 In the conventional control circuit of the cartridge valve 01 shown, the servo valve 02 can only inject pressure oil into the upper control chamber 013 or the lower control chamber 014 to realize the unidirectional motion control of the main valve core 011, which may cause the motion overshoot of the main valve core 011, so the servo valve 02 needs to be fine-tuned for multiple reciprocating movements. In this embodiment, the upper control chamber 013 and the lower control chamber 014 are hydraulically piloted by multiple pilot control valves at the same time, and the opening of the pilot control valve can be adjusted in real time according to the motion state of the main valve core 011 to control the pressure in the upper control chamber 013 and the lower control chamber 014, so as to ensure that the pressure of the upper control chamber 013 and the lower control chamber 014 is just balanced when the main valve core 011 reaches the set position, thereby realizing accurate and rapid control of the position of the main valve core 011. At the same time, the opening of the corresponding pilot control valve can be adjusted according to different requirements to adapt to different back pressure requirements. In addition, the response speed of the control circuit can be effectively improved through the coordinated control of multiple pilot control valves.

[0031] It should be known that the specific structure and working principle of the pilot control valve are well known to those skilled in the art, so they will not be elaborated in detail here. There are many specific structures that can realize bidirectional hydraulic pilot control of the main valve core 011. For the sake of easy understanding, three specific embodiments will be described in detail below. Of course, the pilot hydraulic control of the main valve core 011 includes but is not limited to the following three embodiments.

[0032] Embodiment 1:

[0033] like Figure 2 As shown, the number of pilot control valves is a pair, and the two pilot control valves are connected to each other and to the upper control chamber 013 and the lower control chamber 014 to form an A-bridge structure, and then the opening of the main valve core 011 is adjusted through the A-bridge structure.

[0034] It can be understood that the A-bridge is also called the A-type half-bridge structure. The structural feature of the A-type half-bridge is that there are two liquid resistors for driving the load, and both of the liquid resistors are variable liquid resistors.

[0035] Specifically, in this embodiment, the main valve core 011 can be regarded as a load. The two pilot control valves can both generate a fluid resistance when driving the main valve core 011 to move, and the two fluid resistances can be adjusted by the opening size of the pilot control valve, and then the combination of the two fluid resistances can achieve fast and accurate position control of the main valve core 011. There are many specific implementation methods for forming an A-bridge structure by two pilot control valves. For the convenience of understanding, two specific examples will be used for detailed description below; for the convenience of description, the two pilot control valves can be marked as a first pilot control valve 11 and a second pilot control valve 12, respectively.

[0036] Example 1: Figure 2 As shown, the cartridge valve 01 also includes a spring 012 for resetting the main valve core 011, and the outlet of the upper control chamber 013 is connected to the oil tank. The inlet of the second pilot control valve 12 is connected to the oil pump, and the outlet is connected to the inlet of the lower control chamber 014 and the inlet of the first pilot control valve 11; the outlet of the first pilot control valve 11 is connected to the outlet of the upper control chamber 013, so that an A-bridge structure is formed between the two pilot control valves.

[0037] Example 2: The structure is basically similar to that of Example 1, that is, the outlet of the lower control chamber 014 is connected to the oil tank, the inlet of the second pilot control valve 12 is connected to the oil pump, and the outlet is connected to the inlet of the upper control chamber 013 and the inlet of the first pilot control valve 11; the outlet of the first pilot control valve 11 is connected to the outlet of the lower control chamber 014, so that an A-bridge structure is formed between the two pilot control valves.

[0038] It is understandable that both of the above two examples can meet the requirements of this application, and can be selected according to the actual needs of those skilled in the art. For ease of understanding, the specific control process of the main valve core 011 will be described in detail below using Example 1 as an example.

[0039] When the main valve core 011 needs to be opened or the opening degree is increased, the second pilot control valve 12 can be opened first, and the oil pump can deliver the oil to the lower control chamber 014 through the second pilot control valve 12, and at the same time, the oil in the upper control chamber 013 is discharged back to the oil tank from the outlet. At this time, the main valve core 011 can move the compression spring 012 upward under the drive of the second pilot control valve 12, that is, move in the direction of increasing the opening degree. Since the displacement of the main valve core 011 is controlled only by the second pilot control valve 12 and the spring 012, it is easy to have displacement overshoot or slow response. Therefore, in the above process, the first pilot control valve 11 needs to be opened, and part of the oil of the oil pump can be delivered to the outlet position of the upper control chamber 013 through the first pilot control valve 11 to increase the return oil resistance of the upper control chamber 013. At this time, an A bridge structure can be formed between the first pilot control valve 11 and the second pilot control valve 12. Under the A structure, the pressure difference between the upper control chamber 013 and the lower control chamber 014 during the opening process of the cartridge valve 01 can be adjusted according to actual needs, thereby ensuring that the displacement of the main valve core 011 will not overshoot while also increasing the displacement response speed of the main valve core 011.

[0040] When the main valve core 011 needs to reduce its opening, according to the above-mentioned A-bridge structure, the opening of the first pilot control valve 11 can be increased, while the opening of the second pilot control valve 12 is reduced. Then the amount of oil at the outlet of the second pilot control valve 12 will be reduced, and the fluid resistance in the direction of the first pilot control valve 11 will be reduced, so that the pressure in the lower control chamber 014 is reduced, so that the main valve core 011 can move downward under the elastic force of the spring 012, that is, move in the direction of reducing the opening. At this time, the oil in the lower control chamber 014 can enter the upper control chamber 013 through the first pilot control valve 11 to form a differential structure.

[0041] Embodiment 2:

[0042] like Figure 3 As shown, the number of pilot control valves is a pair, and the two pilot control valves are respectively connected to the upper control chamber 013 and the lower control chamber 014 to form a double C-bridge structure, and then the opening of the main valve core 011 is adjusted through the double C-bridge structure.

[0043] It can be understood that the double C-bridge structure is two single C-bridge structures, specifically, each pilot control valve can form a C-bridge structure. The so-called C-bridge structure is also called a C-type half-bridge structure. Its structural feature is that there are two liquid resistances for driving the load, the first liquid resistance is a variable liquid resistance, and the second liquid resistance is a fixed liquid resistance.

[0044] Specifically, in this embodiment, the main valve core 011 can be regarded as a load, and each pilot control valve can generate a fluid resistance when driving and controlling the main valve core 011. The fluid resistance can be adjusted by the opening of the pilot control valve, so the fluid resistance is a variable fluid resistance. The upper control chamber 013 and the lower control chamber 014 both have two interfaces, one of which is used to connect the pilot control valve, and the other interface can be connected to the oil tank to generate a fixed fluid resistance. There are many specific implementation methods for forming a double C-bridge structure by two pilot control valves. For the convenience of understanding, a specific example will be used for detailed description below; for the convenience of description, the two pilot control valves can be marked as the first pilot control valve 11 and the second pilot control valve 12 respectively.

[0045] In this embodiment, Figure 3 As shown, the outlets of the upper control chamber 013 and the lower control chamber 014 are both connected to the oil tank, the inlets of the two pilot control valves are both connected to the oil pump, the outlet of the first pilot control valve 11 is connected to the inlet of the upper control chamber 013, and the outlet of the second pilot control valve 12 is connected to the inlet of the lower control chamber 014; and thus the first pilot control valve 11 and the second pilot control valve 12 can form a C-bridge structure. For ease of understanding, the specific working process of this embodiment will be described in detail below.

[0046] When the main valve core 011 needs to be opened or the opening degree needs to be increased, the opening degree of the second pilot control valve 12 can be controlled to increase, and the opening degree of the first pilot control valve 11 can be reduced at the same time. At this time, the amount of oil delivered by the oil pump to the first pilot control valve 11 is less than the amount of oil delivered to the second pilot control valve 12; that is, the pressure in the lower control chamber 014 is higher than the pressure in the upper control chamber 013, and the main valve core 011 will move upward, that is, move in the direction of increasing the opening degree. In the process of the main valve core 011 moving upward, by controlling the opening degrees of the first pilot control valve 11 and the second pilot control valve 12 respectively, the moving speed and position of the main valve core 011 can be quickly and accurately adjusted.

[0047] When the opening of the main valve core 011 needs to be reduced, the control process is opposite to the above process; that is, the opening of the second pilot control valve 12 is controlled to be reduced, and the opening of the first pilot control valve 11 is increased. At this time, the amount of oil delivered by the oil pump to the first pilot control valve 11 is greater than the amount of oil delivered to the second pilot control valve 12; that is, the pressure in the lower control chamber 014 is lower than the pressure in the upper control chamber 013, and the main valve core 011 will move downward, that is, move in the direction of reducing the opening.

[0048] It should be noted that in the solution of this embodiment, the first pilot control valve 11 and the second pilot control valve 12 can respectively drive the main valve core 011 to move up or down by different opening degrees, so there is no need to install the spring 012 in the cartridge valve 01 of this embodiment.

[0049] It can be understood that in the present embodiment, since the outlets of the upper control chamber 013 and the lower control chamber 014 are directly connected to the oil tank, the outlet pressures of the upper control chamber 013 and the lower control chamber 014 are relatively small as the fixed hydraulic resistance of the C-bridge structure, so that the first pilot control valve 11 and the second pilot control valve 12 need to pass through a higher oil pressure to form pressure in the upper control chamber 013 and the lower control chamber 014; that is, the outlets of the upper control chamber 013 and the lower control chamber 014 are directly connected to the oil tank, which will produce a pressure dead zone, and this pressure dead zone will reduce the dynamic control of the pilot control valve over the main valve core 011.

[0050] Therefore, in order to improve the dynamic control capability of the main valve core 011, that is, the pilot control valve only needs to maintain a stable small opening when opening, a fixed damping for increasing the return oil pressure can be installed in the pipelines connecting the outlets of the upper control chamber 013 and the lower control chamber 014 to the oil tank.

[0051] Embodiment three:

[0052] like Figure 4 As shown, there are two pairs of pilot control valves, and the upper control chamber 013 and the lower control chamber 014 are each connected to a pair of pilot control valves, so that the two pairs of pilot control valves form a double A-bridge structure to adjust the opening of the main valve core 011.

[0053] It can be understood that the double A-bridge structure is two single A-bridge structures, and the specific structural characteristics of the A-bridge structure have been described in the above content, so they will not be repeated here.

[0054] Specifically, in this embodiment, the main valve core 011 can be regarded as a load, and the two pairs of pilot control valves corresponding to the upper control chamber 013 and the lower control chamber 014 can generate two pairs of corresponding fluid resistances when driving the main valve core 011 to move. The two fluid resistances of each pair can be adjusted by the opening of the corresponding pilot control valve, and thus the two fluid resistances of each pair can be used as variable fluid resistances. There are many specific implementation methods for forming an A-bridge structure by two pilot control valves. For the convenience of understanding, two specific examples will be used for detailed description below; for the convenience of description, the four pilot control valves of the two pairs can be respectively marked as the first pilot control valve 11, the second pilot control valve 12, the third pilot control valve 15 and the fourth pilot control valve 16.

[0055] In this embodiment, Figure 4As shown, the inlets of the first pilot control valve 11 and the second pilot control valve 12 are both connected to the oil pump, the outlet of the first pilot control valve 11 is connected to the upper control chamber 013, and the outlet of the upper control chamber 013 is connected to the oil tank through the third pilot control valve 15, so that an A bridge structure corresponding to the upper control chamber 013 is formed between the first pilot control valve 11 and the third pilot control valve 15. The outlet of the second pilot control valve 12 is connected to the lower control chamber 014, and the outlet of the lower control chamber 014 is connected to the oil tank through the fourth pilot control valve 16, so that an A bridge structure corresponding to the lower control chamber 014 is formed between the second pilot control valve 12 and the fourth pilot control valve 16.

[0056] It is understandable that there are multiple specific implementation methods for driving and controlling the main valve core 011 based on the above-mentioned double A-bridge structure; for ease of understanding, two specific control methods are described in detail below.

[0057] Control method 1: When the main valve core 011 needs to be opened or the opening degree is increased, the second pilot control valve 12 and the third pilot control valve 15 can be opened, and at this time, an A-bridge structure can also be formed between the second pilot control valve 12 and the third pilot control valve 15. Thus, the oil pump can deliver the oil to the lower control chamber 014 through the second pilot control valve 12 to increase the pressure of the lower control chamber 014, and at the same time, the oil in the upper control chamber 013 can flow back to the oil tank through the third pilot control valve 15; and in the process of oil reflux, the return oil back pressure can be controlled by controlling the opening degree of the third pilot control valve 15.

[0058] When the opening of the main valve core 011 needs to be reduced, the first pilot control valve 11 and the fourth pilot control valve 16 can be opened, and an A-bridge structure can be formed between the first pilot control valve 11 and the fourth pilot control valve 16. Thus, the oil pump can deliver oil to the upper control chamber 013 through the first pilot control valve 11 to increase the pressure of the upper control chamber 013, and the oil in the lower control chamber 014 can flow back to the oil tank through the fourth pilot control valve 16; and during the oil reflux process, the return oil back pressure can be controlled by controlling the opening of the fourth pilot control valve 16.

[0059] Control method 2: When the main valve core 011 needs to be opened or the opening degree is increased, the first pilot control valve 11, the second pilot control valve 12 and the third pilot control valve 15 can be opened, and at this time, an A bridge structure can be formed between the second pilot control valve 12 and the third pilot control valve 15, and an A bridge structure can be formed between the first pilot control valve 11 and the third pilot control valve 15. Thus, the oil pump can deliver the oil to the lower control chamber 014 through the second pilot control valve 12 to increase the pressure of the lower control chamber 014, and at the same time, the oil in the upper control chamber 013 can flow back to the oil tank through the third pilot control valve 15; and in the process of oil reflux, the return oil back pressure can be controlled by controlling the opening degree of the first pilot control valve 11 and the third pilot control valve 15.

[0060] When the opening of the main valve core 011 needs to be reduced, the first pilot control valve 11, the second pilot control valve 12 and the fourth pilot control valve 16 can be opened, and at this time, an A bridge structure can be formed between the first pilot control valve 11 and the fourth pilot control valve 16, and an A bridge structure can be formed between the second pilot control valve 12 and the fourth pilot control valve 16. Thus, the oil pump can deliver the oil to the upper control chamber 013 through the first pilot control valve 11 to increase the pressure of the upper control chamber 013, and at the same time, the oil in the lower control chamber 014 can flow back to the oil tank through the fourth pilot control valve 16; and in the process of oil reflux, the return oil back pressure can be controlled by controlling the opening of the second pilot control valve 12 and the fourth pilot control valve 16.

[0061] It is understandable that, for the above-mentioned control method 1, when controlling the return oil back pressure, only a single pilot control valve is used to adjust the opening, although back pressure control can be achieved, but the change in the opening of the single pilot control valve will cause a sudden change in the speed of the main valve core 011, thereby affecting its dynamic performance. For the above-mentioned control method 2, the opening of the two pilot control valves of the A bridge structure is coordinated to adjust, which can not only achieve the control of the return oil back pressure, but also ensure the stability of the movement of the main valve core 011.

[0062] In the embodiment of the present application, there are multiple ways to adjust the opening of the pilot control valve. For ease of understanding, a detailed description will be given below using one specific adjustment method. Figures 2 to 4 As shown, the main valve core control circuit also includes a displacement sensor 10 and a control circuit. The displacement sensor 10 is installed on the valve body of the cartridge valve 01 to monitor the movement distance of the main valve core 011. The displacement sensor 10 and the control circuit are connected by signal, so that the displacement sensor 10 can send the monitored displacement data of the main valve core 011 to the control circuit. The control circuit can be connected by signal with each pilot control valve, so that after the control circuit receives the displacement data sent by the displacement sensor 10, it can send a corresponding opening control signal to each pilot control valve according to the preset opening.

[0063] It is understandable that, although the opening control amount of each pilot control valve can be directly obtained according to the preset opening, the opening control amount is a theoretical value. In the actual control process, due to possible problems such as pipeline bending or pipeline leakage, the actual displacement of the main valve core 011 will directly deviate from the theoretical displacement. Therefore, the actual displacement of the main valve core 011 can be monitored by setting a displacement sensor 10, and the actual displacement of the main valve core 011 monitored can be fed back to the control circuit to achieve real-time adjustment of the opening of each pilot control valve. The specific structure and working principle of the displacement sensor 10 are well-known technologies for those skilled in the art, so they will not be elaborated in detail here. There are many specific structures of the control circuit that can realize the above functions. For the sake of convenience, one of the specific structures will be described in detail below.

[0064] Specifically, Figures 2 to 4 As shown, the control circuit includes a controller 13 and a comparator 14 connected by signals. The comparator 14 can receive the displacement data sent by the displacement sensor 10 and compare it with the built-in preset opening. The controller 13 can generate a corresponding opening control signal according to the comparison result of the comparator 14 to send to each pilot control valve respectively.

[0065] It should be known that the specific structures and working principles of the controller 13 and the comparator 14 are well known to those skilled in the art, and thus will not be elaborated in detail herein.

[0066] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A main valve core control circuit, applied to the main valve core control of a cartridge valve, wherein the main valve core is sealingly and slidably mounted on the valve body of the cartridge valve, and is formed with an upper control chamber and a lower control chamber for controlling the movement of the main valve core; characterized in that: The main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber and the lower control chamber; the opening of the main valve core is adjusted by controlling the opening of each pilot control valve; the pressure difference between the upper control chamber and the lower control chamber of the main valve core during the opening adjustment process is cooperatively controlled by a hydraulic bridge structure formed by the cooperation of each pilot control valve; The number of the pilot control valves is a pair, and the two pilot control valves are connected to each other and to the upper control chamber and the lower control chamber to form an A-bridge structure, and then the opening of the main valve core is adjusted through the A-bridge structure; The cartridge valve also includes a spring for resetting the main valve core, and the outlet of the upper control chamber is connected to the oil tank; the inlet of one of the pilot control valves is connected to the oil pump, and the outlet is connected to the inlet of the lower control chamber and the inlet of the other pilot control valve, and the outlet of the other pilot control valve is connected to the outlet of the upper control chamber, so that the A-bridge structure is formed between the two pilot control valves.

2. A main valve core control circuit, applied to the main valve core control of a cartridge valve, wherein the main valve core is sealingly and slidably mounted on the valve body of the cartridge valve, and is formed with an upper control chamber and a lower control chamber for controlling the movement of the main valve core; characterized in that: The main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber and the lower control chamber; the opening of the main valve core is adjusted by controlling the opening of each pilot control valve; the pressure difference between the upper control chamber and the lower control chamber of the main valve core during the opening adjustment process is cooperatively controlled by a hydraulic bridge structure formed by the cooperation of each pilot control valve; The number of the pilot control valves is a pair, and the two pilot control valves are respectively connected to the upper control chamber and the lower control chamber to form a double C-bridge structure, and then the opening of the main valve core is adjusted through the double C-bridge structure; The outlets of the upper control chamber and the lower control chamber are both connected to the oil tank, the inlets of the two pilot control valves are both connected to the oil pump, and the outlets of the two pilot control valves are respectively connected to the inlets of the upper control chamber and the lower control chamber, so that each pilot control valve forms a C-bridge structure.

3. The main valve core control circuit according to claim 2, characterized in that: Fixed damping for increasing the return oil pressure is installed in the pipelines connecting the outlets of the upper control chamber and the lower control chamber with the oil tank.

4. A main valve core control circuit, applied to the main valve core control of a cartridge valve, wherein the main valve core is sealingly and slidably mounted on the valve body of the cartridge valve, and is formed with an upper control chamber and a lower control chamber for controlling the movement of the main valve core; characterized in that: The main valve core control circuit includes at least one pair of pilot control valves respectively connected to the upper control chamber and the lower control chamber; the opening of the main valve core is adjusted by controlling the opening of each pilot control valve; the pressure difference between the upper control chamber and the lower control chamber of the main valve core during the opening adjustment process is cooperatively controlled by a hydraulic bridge structure formed by the cooperation of each pilot control valve; The number of the pilot control valves is two pairs, and the upper control chamber and the lower control chamber are each connected to a pair of the pilot control valves, so that the two pairs of the pilot control valves form a double A-bridge structure to adjust the opening of the main valve core; The inlets of a pair of the pilot control valves are both connected to the oil pump, and the outlets are respectively connected to the inlets of the upper control chamber and the lower control chamber; the outlets of the upper control chamber and the lower control chamber are both connected to the oil tank through the pilot control valves, so that an A-bridge structure is formed between the pair of the pilot control valves corresponding to the upper control chamber and the lower control chamber respectively.

5. The main valve core control circuit according to any one of claims 1 to 4, characterized in that: The main valve core control circuit also includes a displacement sensor and a control circuit. The displacement sensor is installed on the valve body of the cartridge valve to monitor the movement distance of the main valve core. The control circuit is suitable for receiving the displacement data sent by the displacement sensor and sending corresponding opening control signals to each pilot control valve according to a preset opening.

6. The main valve core control circuit according to claim 5, characterized in that: The control circuit includes a controller and a comparator; the comparator is suitable for receiving the displacement data sent by the displacement sensor and comparing it with the preset opening, and the controller is suitable for generating corresponding opening control signals according to the comparison results of the comparator to send them to each of the pilot control valves respectively.

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